Use native byte order instead of little-endian.

index.js

@@ -9,6 +9,7 @@
 
 var stream = require('stream');
 var util = require('util');
+var UInt32Native = require('./native').UInt32Native;
 
 function Input() {
     stream.Transform.call(this);
@@ -38,7 +39,7 @@ Input.prototype._transform = function(chunk, encoding, done) {
             // Nope. Do we have enough bytes for the length?
             if (self.buf.length >= 4) {
                 // Yep. Parse the bytes.
-                self.len = self.buf.readUInt32LE(0);
+                self.len = UInt32Native.read(self.buf, 0);
                 // Remove the length bytes from the buffer.
                 self.buf = self.buf.slice(4);
             }
@@ -86,7 +87,7 @@ Output.prototype._transform = function(chunk, encoding, done) {
         ? Buffer.from(JSON.stringify(chunk))
         : new Buffer(JSON.stringify(chunk));
 
-    len.writeUInt32LE(buf.length, 0);
+    UInt32Native.write(len, buf.length, 0);
 
     this.push(Buffer.concat([len, buf]));
 

native.js

@@ -0,0 +1,15 @@
+var os = require('os');
+
+// Use the native byte-order of the system; can't assume little or big-endianness.
+// ref https://developer.chrome.com/extensions/nativeMessaging#native-messaging-host-protocol
+var isBE = os.endianness() === 'BE';
+var UInt32Native = {
+    read: function(buf, offset) {
+        return isBE ? buf.readUInt32BE(offset) : buf.readUInt32LE(offset);
+    },
+    write: function(buf, value, offset) {
+        return isBE ? buf.writeUInt32BE(value, offset) : buf.writeUInt32LE(value, offset);
+    }
+};
+
+exports.UInt32Native = UInt32Native;

test.js

@@ -3,10 +3,11 @@
 var test = require('tape');
 
 var nativeMessaging = require('./index');
+var UInt32Native = require('./native').UInt32Native;
 
 test('Input', function(t) {
     var buf =typeof Buffer.alloc === 'function' ? Buffer.alloc(17) : new Buffer(17);
-    buf.writeUInt32LE(13, 0);
+    UInt32Native.write(buf, 13, 0);
     buf.write('{"foo":"bar"}', 4);
 
     var input = new nativeMessaging.Input();
@@ -25,7 +26,7 @@ test('Output', function(t) {
 
     output.once('readable', function() {
         var buf = output.read();
-        t.equal(buf.readUInt32LE(0), 13);
+        t.equal(UInt32Native.read(buf, 0), 13);
         t.equal(buf.slice(4).toString(), '{"foo":"bar"}');
         t.end();
     });